1、BRITISH STANDARDBS EN ISO 6145-11:2008Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 11: Electrochemical generationICS 71.040.40g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51
2、g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58National forewordThis British Standard is the UK implementation of EN ISO 6145-11:2008. It is identical with ISO 6145-11:2005. It supersedes BS ISO 6145-11:2005 which is withdrawn.The UK participation in its preparation was entr
3、usted to Technical Committee PTI/15, Natural gas and gas analysis.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct applicati
4、on.Compliance with a British Standard cannot confer immunity from legal obligations.BS EN ISO 6145-11:2008Amendments/corrigenda issued since publicationDate Comments 30 June 2009 This corrigendum renumbers BS ISO 6145-11:2005 as BS EN ISO 6145-11:2008This British Standard, was published under the au
5、thority of the Standards Policy and Strategy Committee on 30 January 2006 BSI 2009ISBN 978 0 580 60363 1EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 6145-11August 2008ICS 71.040.40English VersionGas analysis - Preparation of calibration gas mixtures usingdynamic volumetric methods - Part 11
6、: Electrochemicalgeneration (ISO 6145-11:2005)Analyse des gaz - Prparation des mlanges de gaz pourtalonnage laide de mthodes volumtriquesdynamiques - Partie 11: Gnration lectrochimique (ISO6145-11:2005)Gasanalyse - Herstellung von Kalibriergasgemischen mitHilfe von dynamisch-volumetrischen Verfahren
7、 - Teil 11:Elektrochemische Herstellung (ISO 6145-11:2005)This European Standard was approved by CEN on 30 July 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any
8、 alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by
9、translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germa
10、ny, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManag
11、ement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 6145-11:2008: EForeword The text of ISO 6145-11:2005 has been prepared by Technical Committee ISO/TC 158 “Analysis of gases” o
12、f the International Organization for Standardization (ISO) and has been taken over as EN ISO 6145-11:2008 by Technical Committee CEN/TC N21 “Gaseous fuels and combustible gas” the secretariat of which is held by CMC. This European Standard shall be given the status of a national standard, either by
13、publication of an identical text or by endorsement, at the latest by February 2009, and conflicting national standards shall be withdrawn at the latest by February 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or C
14、ENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, De
15、nmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 6145-11:2005 has been ap
16、proved by CEN as a EN ISO 6145-11:2008 without any modification. Reference numberISO 6145-11:2005(E)INTERNATIONAL STANDARD ISO6145-11First edition2005-10-15Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 11: Electrochemical generation Analyse des gaz Prpara
17、tion des mlanges de gaz pour talonnage laide de mthodes volumtriques dynamiques Partie 11: Gnration lectrochimique ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Procedure 2 3.1 Principle. 2 3.2 Complementary gas 2 3.3 Electrolytic systems for gas generation.
18、 2 3.4 Apparatus 3 3.4.1 Cell construction. 3 3.4.2 Current supply and gas flow control 3 3.5 Gas mixture preparation 3 3.5.1 Complementary gas 3 3.5.2 Voltage supply 3 3.5.3 Calculation of gas mixture content. 4 4 Uncertainty evaluation . 6 4.1 Introduction . 6 4.2 Sources of uncertainty. 6 4.2.1 C
19、omplementary gas flow . 6 4.2.2 Gas generation 6 4.2.3 Absorption of generated gas in the cell electrolyte 6 4.2.4 Effect of moisture content . 6 4.2.5 Effect of temperature 6 4.2.6 Purity of electrolytic chemicals. 6 4.2.7 Impurities in complementary gas 7 4.3 Uncertainty of volume fraction 7 5 Ele
20、ctrochemical cell design. 7 Annex A (informative) Example of a commercial electrochemical cell 9 Annex B (informative) Schematics of electrolytic cells used for gas generation 11 Annex C (informative) Schematic of electrical supply to gas generation cell . 12 Annex D (informative) Decomposition volt
21、ages of solutions between smooth platinum electrodes . 13 Bibliography . 14 BS EN ISO 6145-11:2008 EN ISO 6145-11:2008 (E)iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internation
22、al Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO,
23、 also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical comm
24、ittees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the p
25、ossibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 6145-11 was prepared by Technical Committee ISO/TC 158, Analysis of gases. ISO 6145 consists of the following parts, under t
26、he general title Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods: Part 1: Methods of calibration Part 2: Volumetric pumps Part 4: Continuous syringe injection method Part 5: Capillary calibration devices Part 6: Critical orifices Part 7: Thermal mass-flow contro
27、llers Part 8: Diffusion method Part 9: Saturation method Part 10: Permeation method Part 11: Electrochemical generation Part 3 to ISO 6145, entitled Periodic injections into a flowing gas stream, has been withdrawn by Technical Committee ISO/TC 158, Analysis of gases. BS EN ISO 6145-11:2008 EN ISO 6
28、145-11:2008 (E)vIntroduction This part of ISO 6145 is one of a series of standards dealing with the various dynamic volumetric methods used for the preparation of calibration gas mixtures. Electrochemical gas generation can be used to produce calibration gas mixtures containing calibration component
29、s which, because of their corrosive nature or low content, are unlikely to be stable in high-pressure cylinders. BS EN ISO 6145-11:2008 EN ISO 6145-11:2008 (E)blankBS EN ISO 6145-11:2008 EN ISO 6145-11:2008 (E)1Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Par
30、t 11: Electrochemical generation 1 Scope This part of ISO 6145 specifies a method for the preparation of calibration gas mixtures by using electrochemical generation of a calibration component and introduction into a complementary gas flow. By alteration of the gas flow or the charge passed through
31、the cell electrolyte, it is possible to change the composition of the gas mixture. The relative expanded uncertainty of the calibration gas content, U, obtained by multiplying the relative combined standard uncertainties by a coverage factor, k = 2, is not greater than 5 %. The method described in t
32、his part of ISO 6145 is intended to be applied to the preparation of calibration gas mixtures in the volume fraction ranges (0,1 to 250) 106. NOTE 1 Gases that can be produced by electrochemical generation are oxygen (O2), hydrogen (H2), hydrogen cyanide (HCN), hydrogen sulfide (H2S), chlorine (Cl2)
33、, bromine (Br2), chlorine dioxide (ClO2), ammonia (NH3), nitric oxide (NO), nitrogen (N2), carbon dioxide (CO2), phosphine (PH3), arsine (AsH3) and ozone (O3). NOTE 2 The merits of the method are that a stable calibration gas mixture can be quickly prepared within minutes. NOTE 3 Gas blending system
34、s based on electrochemical generation and thermal mass flow controllers, with the facility of computerization and automatic control, are commercially available. An example is given in Annex A. 2 Normative references The following referenced documents are indispensable for the application of this doc
35、ument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6143, Gas analysis Comparison methods for determining and checking the composition of calibration gas mixtures ISO 6145-1, Gas an
36、alysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 1: Methods of calibration ISO 6145-7:2001, Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 7: Thermal mass-flow controllers BS EN ISO 6145-11:2008 EN ISO 6145-11:2008 (E)2
37、3 Procedure 3.1 Principle Electrochemical gas generation is a fundamental method in which the quantity of the calibration gas component generated is proportional to the charge passed. The proportionality factor is the reciprocal of the Faraday constant the electrical charge carried by one mole of el
38、ectrons (or singly charged ions), which is equal to the product of the Avogadro constant (NA) and the charge of an electron (e). F = NA e (1) where F is 96 485,341 5 C/mol with a relative uncertainty of 4,0 108(see References 1, 2 and 3). The passage of accurately determined electrical current throu
39、gh a cell determines the gas output provided the conditions given in Clause 5 are applied. 3.2 Complementary gas The flow rate of complementary gas shall be determined by one of the methods given in ISO 6145-1. 3.3 Electrolytic systems for gas generation Table 1 lists some examples of gases which ca
40、n be prepared in quantitative yield by direct electrolysis, using platinum and other electrodes. Also included is an example of the suppression of an unwanted constituent by adsorption on activated carbon surrounding the appropriate electrode. Table 1 Electrolysis systems for gas generation Gas requ
41、ired Electrolysis system Gas liberated at other electrode Yield mole of required gas per charge numerically equal to Faraday number O2or H2Pt, H2SO4, Pt Pt, K2SO4, Pt Pt, KOH, Pt H2or O21/4 (O2) 1/2 (H2) O2Pt, H2SO4, Hg2SO4, +C, Hg Pt, neutral solution, active C Pt, KOH, HgO, +C, Hg Pt, KOH, CdO, Cd
42、 nil 1/4 N2Pt, N2H4, H2SO4, Pt H21/4 Cl2Pt, NaCl, Pt H21/2 CO2Pt, H2C2O4, Pt H21 NO Pt, (NOH)SO4, + H2SO4, Pt aO21 aThis system has also been used for the generation of nitrogen dioxide 4.BS EN ISO 6145-11:2008 EN ISO 6145-11:2008 (E)33.4 Apparatus 3.4.1 Cell construction Cell construction shall be
43、designed to ensure that the generated calibrated component is transferred into the complementary gas stream at maximum efficiency suitable for calibration purposes. Some of the conditions that shall be fulfilled for the operation of an electrolytic cell used for this purpose are given in Clause 5. E
44、xamples of electrolytic cells are given in Figures B.1 and B.2. 3.4.2 Current supply and gas flow control 3.4.2.1 The content of the calibration gas produced from the system is dependent on three factors: a) the current supplied through the cell which generates a volume flow rate of the calibration
45、gas component; b) the (volume) flow rate of the complementary gas; and c) the cell efficiency. NOTE Cell efficiency is the fraction recovery of calibration component over the calculated quantity generated by the current supplied to the cell (see 4.2.3). It depends on the design of the cell. Practica
46、l hints on design are given in Clause 5 and an example is given in Annex C. 3.4.2.2 A battery, capable of supplying voltage in the range 0,5 V to 1,0 V, and a milliamperemeter with a measurement range of 0,5 mA to 5,0 mA with an uncertainty of 1,0 %, are suitable. DC generators are an alternative bu
47、t may pass an AC ripple, which can affect the electrolysis process. 3.4.2.3 A flow measuring unit (e.g. a thermal mass-flow meter) that has been calibrated for the complementary gas between a volume flow rate of 0,2 l/min and 5,0 l/min with an uncertainty of 1 % is suitable. NOTE Methods for the mea
48、surement of the flow rate of the complementary gas are given in ISO 6145-1, which also describes the procedure for calibration of the thermal mass-flow meter. 3.5 Gas mixture preparation 3.5.1 Complementary gas The calibration gas mixture shall be prepared by passing the chosen complementary gas thr
49、ough the calibrated thermal mass flow controller, set at known flow, through the cell. If the complementary gas is air, the supply to the controller may be managed with a small air pump. Other complementary gases may be chosen by using a regulated supply from a high-pressure cylinder to the controller. The complementary gas shall be allowed to purge out the cell for 2 min and then the cell voltage supply required for the electrolysis shall be switched on. The purity of the complementary gas shal
